For those strugling with ?-8, put all squads on the top camp. This way they all arrive at the middle at the same time (due to not running further after teleport). This way each squad will end up on one lane. However this does mean each squad has to handle 1 pest. And they are pretty tough on this stage.

I made a special list for this, instead of the lazy auto group I want to from top to bottom and placed my strongest (highest attack) in each slot, as I reach the 4th group, I went to the second column and did the same. This way each party end up at roughly the same attack power. Then I just checked to see if I wanted to swap a few so each party had 1 of each type.

Went with the highest attack power helper squad I could find. Was still a close call, some pests barely went down for me. Good luck to everyone.

Putting all squads on the bottom camp works too, like someone else mentioned. At least, that's what I did. I didn't 3 medal it though, because all 5 of my squads decided to go fight the same boss at the end, leaving the second boss all alone.. -.-

Only way to reach the other boss is by sending a squad through the bottom portal in the middle of the stage. This will be the 5th squad to reach the arrow space that splits the squads to the pests. So try to manipulate it a bit so you know the 5th squad can handle a pest group and a boss.

Note that all pests on the map are weak to slice.

Indeed, placing all squads on bottom camp works. My squads are all balanced in terms of power, speed & type. Got 3 medals first time using this method.